Deer exclusion and invasive plant control enhance native plants but fail to restore diversity in a peri-urban forest

Two of the most pervasive threats facing Eastern Deciduous Forests are the long-term overabundance of white-tailed deer and the spread of non-native invasive plants. Overbrowsing of native plants leads to the extirpation of palatable species and intensifies invasive plant spread, leading to regeneration failures. Fragmented peri-urban habitats, the transition zone between the urban and rural interface, are particularly vulnerable to overabundant deer and invasive species. Here, we evaluate the effects of deer exclusion through fencing and a single instance of invasive plant removal on understory plant community dynamics in a degraded peri-urban habitat with high deer densities. We found that 4 years following our treatments, neither excluding deer nor removing invasives or the combination promoted native plant diversity. However, deer exclusion enhanced total native cover and vertical diversity and combined treatments increased vertical native diversity and native plant heights. Our findings highlight that while fencing fails to restore native diversity, removing invasive plants reduced invasive vertical diversity, and reducing deer browsing pressure improves native cover and vertical diversity, especially in upper understory layers. In peri-urban habitats with deer overabundance, fencing, invasive removals, and the focus on restoring browse-tolerant species offers a realistic path for restoring native plant understory composition.